Project Summary Despite marked progress in the rate of cure among patients with acute leukemia, a diagnosis of acute myeloid leukemia (AML) portends a poor prognosis for pediatric and adult patients, especially for high risk subsets of AML, such as MLL-rearranged or NMP1 mutant AML. Creative approaches to identifying and characterizing new therapeutic targets are critically needed. New insights into the biology of AML reveals alterations in multiple epigenetic regulators that drive oncogenic transcriptional programs. In this proposal, therefore, we consider AML a disease of a dysregulated transcriptome. We hypothesize that activation of transcription factors drives cancer cell proliferation and blocks differentiation. As such, new studies from our laboratories and others have clearly identified dependencies on several transcription factors (TFs), and specifically zinc finger (ZnF) TFs, that influence aberrant gene regulation in AML. Using a multidisciplinary approach that combines chemical biology and leukemia biology, we will explore the efficacy of degrading the ZnF TFs IKZF1, IKZF2 and ZFP64 with immunomodulatory-based drugs (IMiDs) in AML. First, we will further explore degrading IKZF1 with lenalidomide in combination with the epigenomic inhibitors of DOT1L and MENIN. While inhibition of either DOT1L or MENIN alone causes AML cells to differentiate, co- treatment with lenalidomide induces cell death. Now, we seek to understand the molecular mechanisms governing this synergistic effect in order to guide combination drug therapy in the clinic. Second, we will explore degradation of IKZF2, which we have recently identified as a TF that drives leukemia stem cell self-renewal while inhibiting differentiation. We hypothesize that selective degradation of IKZF2 will lead to rapid cell differentiation and death. We will model IKZF2 degradation in AML in order to study the biological effects as well as test new molecules that can degrade IKZF2 directly. Third, we will exploit our medicinal chemistry and chemical biology platform to develop degraders selective for ZFP64, a newly described TF that directly controls the expression of MLL fusion oncoproteins. Using our expertise in IMiD-based drugs, we will screen for and optimize degraders of ZFP64 to test in AML cells. The immediate objective of this research is to functionally characterize the role of ZnF transcription factors in AML, leveraging a highly collaborative Program of Investigators in chemical biology, structural biology, leukemia biology, cancer modeling, and epigenome science. The long-term goal is to increase AML cure rates by targeting gene regulatory pathways.